General - Siemens SINAMICS G120P Operating Instructions Manual

General

Description
In converters with no regenerative feedback capability, the energy that occurs in the drive
train under regenerative conditions is fed back to the DC link where it is reduced via braking
resistors.
The braking resistor is connected to the Braking Module. The distance between the Braking
Module and braking resistor must not exceed 100 m. This enables the resulting heat loss to
be dissipated outside the switchgear room.
Resistors with ratings of 50 kW are available.
To boost performance, Braking Modules and braking resistors can be connected in parallel.
Since the braking resistors can be used in converters with a wide voltage range, the voltage
can be adjusted (for example, to reduce the voltage stress on the motor and converter) by
setting the response thresholds on the Braking Module.
A thermostat monitors the braking resistor for excessively high temperatures and issues a
signal on a floating contact if the limit value is exceeded.
Fire hazard due to overheating when permissible connection cable lengths are exceeded
Excessively long Braking Module connection cables can cause components to overheat
with the associated risk of fire and smoke.
• The lengths of the Braking Module connection cables may not exceed 100 m.
Fire hazard due to overheating because of inadequate ventilation clearances
Inadequate ventilation clearances can cause overheating with a risk for personnel through
smoke development and fire. This can also result in increased failures and reduced service
lives of braking resistors.
• It is essential that you maintain a ventilation clearance of 200 mm on all sides of the
Braking resistors
Operating Instructions, 10/2016, A5E32845373B AD
WARNING
WARNING
component with ventilation grills.
2
9